Acne is a highly prevalent inflammatory skin condition involving sebaceous sties. Although it clearly develops from an interplay of multiple factors, the exact cause of acne remains elusive. It is increasingly believed that the interaction between skin microbes and host immunity plays an important role in this disease, with perturbed microbial composition and activity found in acne patients. Cutibacterium acnes (C. acnes; formerly called Propionibacterium acnes) is commonly found in sebum-rich areas and its over-proliferation has long been thought to contribute to the disease. However, information provided by advanced metagenomic sequencing has indicated that the cutaneous microbiota in acne patients and acne-free individuals differ at the virulent-specific lineage level. Acne also has close connections with the gastrointestinal tract, and many argue that the gut microbiota could be involved in the pathogenic process of acne. The emotions of stress (e.g., depression and anxiety), for instance, have been hypothesized to aggravate acne by altering the gut microbiota and increasing intestinal permeability, potentially contributing to skin inflammation. Over the years, an expanding body of research has highlighted the presence of a gut–brain–skin axis that connects gut microbes, oral probiotics, and diet, currently an area of intense scrutiny, to acne severity. This review concentrates on the skin and gut microbes in acne, the role that the gut–brain–skin axis plays in the immunobiology of acne, and newly emerging microbiome-based therapies that can be applied to treat acne.

This study examined prevalence and risk factors of periodontitis in representative samples of Korean adults, with and without diabetes mellitus (DM). Data from the 2012 Korean National Health and Nutritional Examination Survey were analyzed. A total of 4,477 adults (≥ 30 years old) were selected from 8,057 individuals who completed a nutrition survey, a self-reported general health behavior questionnaire, an oral examination, an oral hygiene behaviors survey, and laboratory tests. DM was defined as a fasting plasma glucose ≥ 126 mg/dL, or self-reported diagnosed diabetes, or current use of oral hypoglycemic agents and/or insulin. The community periodontal index was used to assess periodontitis status and comparisons between the periodontitis and the non-periodontitis group, were performed, according to the presence of DM. Risk factors for periodontitis in adults with DM and without DM were evaluated by multiple logistic regression analysis. The prevalence of periodontitis was significantly higher in adults with DM (43.7%) than in those without DM (25%, p < 0.001). In adults without DM, risk factors for periodontitis were older age, male, urban habitation, waist circumference, smoking, oral pain, and less frequent tooth brushing. Significant risk factors for periodontitis in adults with DM were the smoking, oral pain, and not-using an oral hygiene product. Adults with DM have an increased risk of periodontitis than those without DM. Current smoking and oral pain increase this risk. Using an oral hygiene product can reduce risk of periodontal disease in adults with DM.

Kim MJ, et al. J Korean Med Sci. 2010 Dec;25(12):1828-1830. http://dx.doi.org/10.3346/jkms.2010.25.12.1828